7.18 D Meg Flashcards
Jobs are split up in what 3 areas
Preparation
Safety
The task in hand
What should you do when working in electrical equipment
Disconnect or Trip C/Bs
Disconnect batteries
What should you do when working in any pressurised systems
De pressurise them
How do you remove rivets
Use a drill the same size as the rivet diameter
How can you remove welded areas
Melt the weld
How do you take apart adhesive areas
Destroy the bond
What should you do after re assembly
Always test it
What is Cat B not allowed to do
Authorise to certify manufactur or aircraft
When paint in metal to metal areas is removed what stripper should you us
Only one that is stipulated in the AMM
What is the purpose of a sealant
Used to contain fuel, maintain cabin pressure, reduce fire hazards, exclude moisture, prevent corrosion and fill gaps
What is the consistently of a sealant
Applied as wet and then cured to a rubbery solid compound
What are the four levels of sealing
Absolute
Extensive
Intermediate
Limited
What is fillet seal
Applied at edges of structural joints
(Must be on both sides of seam) (use with a gun)
What should you do if a fillet seal has air bubble in
They must be worked out
What are injection seals
Applied to fill channels and holes that occur due to structural design
What should you do when using an air gun
Never fulling empty it to prevent air in the sealant
What is faying surface sealant
A layer of sealant sandwiched between two fastened mating surfaces
What is the purpose of faying surface sealant
To prevent corrosion and leak trancing in fuel tank
What is a aerodynamic smoother sealant used on
A/c exterior skin gals are filled and surface fares for aerodynamic smoothness
What material should you nit use aerodynamic smoothness on until is is hard and tough
Zinc- chromate until primer is hard and tough
What is fastener seal used for
A variation of one of the basic sealing processes
What is prepack seal
Used to fill structural cavities that are enclosed after assembly and can’t be injected properly
How are brush coat seals put in place
By brushing the sealant into place
What is a seal plane
Structural boundary where the continuity of the seal is established (barrier beyond which the fuel can’t pass)
What is a seal compound
Synthetic rubber materials that are applied in a flow consistency and then cure by chemical reaction into a solid
What are the two categories of a compound
Silicone and non silicone
What are the characteristics of silicone
Normally white, red or grey and used where heat resistance is required
What are the characteristics of non silicone
An6 colour, used where heat resistance is not required
What are the classifications of sealants
A- F
What is a Class A sealant
Brush coat sealant
What is a Class B sealant and what is it
Filleting sealant
Heavy consistency with low slump properties
What is a Class C sealant and what is it
Faying surface sealant
Medium consistency for good spreadability
What is a Class D sealant
Hole filling sealant
Similar consistency to B
What is a Class E and F sealant
Sprayable sealant
What is the application time
When the sealant has thawed and can be used (in hours)
What is not applicable for a one part sealant
The application time
What is the squeeze out life
After thawing during which a faying sealant can be squeezed out of a joint when fasteners are installed
What is the tack free time
After thawing the sealnt has cured sufficiently so will not transfer to the finger or plastic film
What is the cure time
Time for sealant to cure firmly enough that can be handled without damage
What can accelerate the cure time
Heat
What temperature do a sealant start to bubble at
120 degrees FARENHEIGHT
For fastener sealing in a fuel tank what is used
Metal seal caps normally aluminium
How can you tell that a two part sealant is mixed properly
Even colour throughout
What could incomplete mixing cause
May affect cure time and performance
What are the three methods of mixing
Hand mixing
Machine mixing
Cartilage hand mixing
Can you re freeze a sealant
No
What could happen if you use a cold sealant instead of a room temp sealant
Will not adhere to the structure
What is the most common cartilage hand mixing
SEMKIT two part material injection
What are the two stages of cleaning before sealing
Preliminary cleaning
(Removal using a stiff brush and solvent)
Final cleaning
(Dampen clean wiping material)
What temperature should you make sure the material you are sealing to is before sealing
5p degrees Fahrenheit
